Telephone-call-locating system.



T. G. MARTIN & J. ERICKSON.

TELEPHONE CALL LOCATING SYSTEM.

'APPLICATlON FILED DEC. 6. 1906.

1 ,1 83,821 4 Patented May 16, 1916.

e 2 g s Q3 m g M m; m m mmqaim Q Sb w 0 *3 To all whom it may concern TALBOT G. MARTIN AND JOHN ERIGKSON, OF CHICAGO, ILLINO IS, A SSIG-NORS, MESNE ASSIGNMENTS, T FIRST TRUST AND SAVINGS BANK, TRUSTEE, OF

. CHICAGO, ILLINOIS.

.Beit known that we,'TALBo1 Gr. MARTIN and JOHN ERIoKsoN, both citizens of the United States of America, and residents of ,Chicago, Cook. county, Illinois, have invented a certain new and useful Improvement in Telephone-Call-Locating Systems,

a of which the following is a specificatlon.

Our invention contemplates the provision of means for locating calls in an automatic telephone exchange system.

and prevents a release of the connection between the two lines. Thus all calls coming .onto the complaining subscribers line can be traced until the call complained of is .finally located. With this arrangement an alarm or signal is. preferably given as soon I i as theline to which the call-locating device substation #500 has allotted to it the,first-"' selector Act the type described in United has been applied is called. It will be under-- stood, of course, that our call-locating device can be temporarily applied to the'line of any subscriber who wishes calls to be traced. When the central station attend-- ant gets the signal he immediately traces the connection back to the calling line; Other uses will be obvious and will occur to those skilled in the art. I "The accompanying drawing shows diagrammatically two substations #500 and #220 connected by means of central ofiice automatic switching apparatus involving our invention; In the said office the" calling States Patent No. 8l5,321,.granted March 13, 1906, to Keith, E'rickson and Erickson.

It willbe noticed that the central battery B has its positive terminal preferably.

grounded. The operating relays" othe central switches are normally connected to the non-grounded terminal of said battery, so that the subscriber by grounding his line conductors may operate the said switches, as.

is usually the custom in systems ofthe class in connectionwithwhich we have elected to illustrate our invention.- In addition to" the said first-selector there is shown at the central office a connector C which is \an'im- Specification of Letters Patent.

For example," suppose some subscr ber complains that TELEPHONE-CALL-LOCATING SYSTEM.

Erickson, and another first-selector D allotted to the called line. The connector C 3 is the. same as the patented connector, except that the release magnet -term'inal (which, 1n the said patent, is, connected directly with the battery lead) conneotswith.

the battery lead through two contact springs PatentedMa 16. 122% a.

Application filed December 6, 1908. Serial No. 346,547. 1 i i i which are controlled by a relay in the prlvate wipe-r circuit, so that when the side switch of the connector is'in thrd position, the private wiper instead of loci 1g connected directly to ground is in this case connected to ground'through the said relay. Furthermore, the middle spring (controlled by the tion. The fir'stseIectQr'D is exactly like the 'first-selector'A, with the addition of the relay and vibrating bell shown atH, which constitute a part of the selector D and which may be attachedto any first-selector in the central office. At E is shown a ring r genbac k-bridge relays M) of the said patent is omltted from the connector of our inven" switch-hook 3, induction-coil 4: which con i sists of'the primary windin 5 and second ary winding 6, transmitter ringer 8 and battery 9'. In addition to the above-menground impulses to one side of the. line.-

ti oned parts there is provided an impulse 2 wheelIlO-Whioh has the usual vertical impulse teeth 11' that are adapted to operate The impulse wheel also carries the rotary impulse tooth 13 which operates the rotary impulse spring'l-i for grounding'the rotary side of the line. The said impulsea heei is rigidly connected to the same shaft to which the substation dial is secured. The twitch hook has. radiating from its body nun).-

her of 0am arms 15, 1'6 andl'Z and'is pivot- :ally secured to-the keyboard. Thcam arm 15 controls the 1so-called locking; arm 18 which is.used to lock the dial while the re ceiver is on the hook. When the cooperatmg' ground springs 19 and QO engage', the

ground post 21 is then connected'to the sub station ground G. The cam arm 16, when the switch-bookie down, maintains a, con- I tact with the spring 22, thereby bridging the ringer 8 across the line. Thesprings 2.3

and 24 are then disengaged, and the pri-- mary circuit including the primary winding 5, transmitter 7 and local. battery 9 is interrupted- Furthermore, when the switchhook is down the spr ngs .32. and 33 are dis-- engaged; but when the'receiver is removed from the switch-hook the 'said-- springs 'engage, thereby bridging across the line the secondary circuit.

The signaling device whereby a subscriber may signal another after connection has been established-comprises a push button 25 and a spring 26 which normally engages the contact point 27; but when the button 25 is pressed the spring 26 leaves the contact point 27 and-engages the contact point 28, whichlatter is connected with the substation ground G; Means whereby the subscriberv may release the central station apparatus brought-into service comprises three springs29, 30 and 31 known as the release springs, and so controlled by the cam arm.

17 that when the switch-hook descends the three release springs are brought into contact, thereby grounding both of the sub scribers line conductors simultaneously. If

the subscriber at -substation #500, for example, wishes to call the subscriber at sub- 1 station #220 he first removes the receiver 2 from the switch-hook 3, thereby placing the substation ground G 'in connection with the 1 scriber in making a" call operates his dial ground 'post 21, through the cooperating ground springs 19 and 20. The calling subjonce for each digit of the desired'number.

, On the return motion of the dial, at each operation, first the vertical impulse teeth engage the vertical impulse spring 12, and then therotary impulse tooth engages the rotary .j impulse spring 14, forcingsaid springs into contactfwith the ground post 21 and as a re- Sul-t. grounding the vertical and rotary line conductors 34 and 35, respectively. After the first digit is called the first-selector-shat't wipers 36 37 and 38 are raised to the second level offlthe line and private banks as follows: When the spring 12 engages the ground post 21 an energizing circuit is established throughthe vertical relay 39 of the Q first selector'Ag'" The current injthis circuit ,conductor'34, sideswitch wiper. 40, contact -flows"fromground G through the springs 2Oand 19Ito the ground post 21, thence to the verticalf'impulse'spring 12, vertical line i point 41, vertical line relay 39, .through'the {-bridge-cut-ofi springs 42 and 43 to the battery'lead '44, thence through battery B and i linetrelay'39'isenergized the springs 45 and to g'roundG, Each time that the vertical 46 areipressed' into-engagement, and an en- "ergizing circuit is established through the verticalim'agnet 47 .The circuitthrough the 'saidmagn'et extends from ground G to the springs 45 and 46, private'magnet springs 49 and 48, vertical magnet 47 to the battery lead 44, thence through battery B and toground G. The vertical magnet being operated twice the first-selector switch shaft and wipers 36, 37 and 38 are carried to a level with, the'contact points that constitute the terminal of thetrunk line leading to the connector C; Following the vertical impulses the rotary impulse spring 14 comes into contact with the ground post 21, thereby grounding the rotary line conductor 35 once and energizing the rotary line relay 50 of the first-selector once. The path of the en ergizing circuit may be traced as follows:

fronrthe substation ground G through the springs 20 and 1.9 to the ground post 21, 1'0- tary impulse spring 14, rotary line conductor 35, sideswitch wiper 51, contact point 52, rotary line relay 50, bridge-cut-oif springs 53, 42 and 43 to the battery lead 44,

thence through battery B and to ground G. I The rotary line relay 50 upon energizing closes the springs 54 and 45 in contact, thereby closing an energizing circuit through the private magnet 55 which extends from ground G through the springs 45 and 54, private magnet 55 to the battery lead 44, thence through battery B and to ground G.

"The private magnet 55 being energized for a moment, the side switch of the first-selector A passes from first to second position, thereby permitting the Side switch wiper'56 to engage the contact point 57, thus closing a circuit through the rotary magnet 59. The

connectorswitch C. ,But if the first trunk line is busy, assuming that the trunk leading to the said connector lcads'ofl' from thefirst set of contacts of the second level, it is prote'cted, as is well known, by a positive guarding potential, and an energizing circuit is established through the private magnet 55 when the private wiper 38 strikes 1 the grounded private bank contact, thereby retaming the side switch 1n second position and 'maintainmg the energizing circuit through the rotary magnet 59 in a well known manner. However, as soon as the private magnet is 'deenergized, the side' switch is tripped to third position; but if there are no busy contacts to be passed over, as assumed in the first instance, then the rotary magnet 59, as is well known, trips the side switch to third, position, with the result that the side switch wipers 40, 51, 56

through battery B and to ground The and 60 engage the respective contact points i 61, 62, 63 and 64, thus extending the subscribers line conductors 34 and 35 to the connect'r C, by sending impulses to the trunk conductors 65 and 66. The subscriber rotates the dial, as described, for the second digit 2, thereby grounding the vertical and rotary line conductors 34 and 35, which causes the energization of the connector vertical and rotary line relays 67 and 68, the

' It flows over the following path: from ground former twice and the latter once. lhe current for energiznig the vertical relay 67 G throughthe springs 20 and 19 to the ver .tical impulse sprin '12, vertical line con- *L': doctor 3%, side switch wiper 40, -first-selector shaft wipcr'36, conductor 65, vertical line relay 67 to the battery lead 44, and through battery B to ground G. Each time Y that the vertically relay 67 is energized, the

line relay springs 69 and 70 are pressed into contact, thereby closing an energizing circuit through the vertical magnet 71 over the following pathi from ground G to the springs 69. and 70 rivate ma net sorin s .2 and 73 7p a b 9 side switch wiper 74, contact point 75, vertical magnet 71 to the battery lead 44, thence vertical magnet is thus energized and operates to raise the shaft and shaft wipers one step at a time until the said wipers are carried two steps to the level 111 which are located the terminal contacts of the 11 he #220.

The, impulses to the vertical side of the line being .toll owed the ground impulse to the rotary side, when the rotary impulse spring strikes the ground post 21, the rotary line relay 68 of the connector becomes energized through the following path: from ground G to the springs 20 and 19, ground post 21, rotary impulse spring 14, rotary line coniliilductor 35, side switch wiper Shaft Wiper 37, trunk conductor 66, rotary line relay 68 to the battery lead 44:, thence through battery B and to ground G. The energization of the rotary line relay 6% causes the energization of the private magnet 76 over a circuit extending from ground G through the springs 69 and 77 to the private magnet 76 and to battery lead 44, thence through battery B and to ground G. As a result the connector-side switch and wipers 78, "9, 89 and 74- are released from first to second position The last digit being naught, the sub sci oer operates the dial as previously. de scribed, grulnding' the vertical line ductoititen dines and the rotary lino mn-- ductor 35 once. The vertical and rotary line relays 67 and 68 are operated over previouslytraced circuits. However, when the line relay springs 69 and 70 engage, a circuit is closed through the rotary magnet 81 instead of through the vertical magnet 71. The energizing circuit extends from ground G through the line relay springs 69 and 70, private magnet springs 72 and 73, side switch, wiper 74, contact point 82, rotary magnet 81 to the battery lead 44, thence through battery B to ground G. Each time that the rotary magnet is energized it rotates the shaft wipers 83, Sal and 85 one step ata time until: the said wipers are carried into engagement with the normal conductors 86, 8'7 and 88%hatjlead to thecalled subscribers line. /fl.

The energization of the rotary line relay 68, as previously stated, completes an energizing circuit through the private magnet 76 which now operates with one of two results', namely the release of the sideswitch from second to third position and the establishment of connection between calling and called lines, it the latter is not busy; or the so-called busy release of the connector if the called line is busy, which releases is brought about as follows: If the called line is busy a guarding potential appears at the private bank contact into engagement with which the private wiper 85 has previously been rotated; then when the private magnet 7 6 energizes as a result of grounding the rotary line conductor as explained, the private springs 132 and 133 are brought into contact while the side switch wiper is in second position, with the result that an energizing circuit is established through the release magnet 190 over the following circuit: from the grounded private bank contact to the private ,wipcr 85, thence through the relay 90, side switch wiper 80, contact point 89 to the private springs 133 and 132, thence through the release magnet 100 and through the springs 99 and 98 to the battery lead 44, thence through battery B to ground G.

' It will be observed that although the current in this'release circuit passes through the relay 90, the spring 99 controlled by.

said relay is given sufiicient tension to prevent the armature of said relay from being operatively attracted when in series with the release magnet 100, which is ordinarily siXty ohms. The said relay 90 is adapted to operatively energize when connected inser es with the battery, B through thirty.

ohms. Therefore, when'the release magnet 100 energizes, as explained, the connector ,switchshaft and side switch are restored to normal condition, with the result that the line and private wipers 83, 54a and are o a i from the normal conductors 86, 87 and o..,

the wiper 85, upon di;:- 1

- connecting from the-private normal conductor 88, destroysthe energizing circuit for the release magnet The connector side switch being thus thrown into first position,

then when a-i-calling'subscriber presses his signaling button25 and. grounds the vertical line conductor 34; by pressing the. spring as onto the ground (3011920928, he energizes the -connector vertical line relay 67 over circuits that'have been described. The said relay in turn energizes the vertical magnet 71 in a 7 well known manner, raising the switch-shaft and permitting the 'ofi-normal springs 93 andr9 ijto pass into engagement, as a result signal the subscriber, understanding that. I, the desired line is busy, will restore hisv re vertical and rotary'line conductors 3 1 and closing a busy signaling circut through thecalling subscribers station, over-circuits that are wellunderstood; Upon hearing the busy ceiver to the switch-hook, grounding the simultaneously, energizing the line relays 67 and 68 of the connector C simultaneously,

and pressing the trunk-release springs 101 and 102 into contact. The engagement of said springs establishes an energizing circuit through the release magnet 100 in series with the back1'ele'ase relay 103 of the selector A, and produces the release of the switches, 'aswill be hereinafter more fully described. Y

. The foregoing is, there-fore, an eXplana-. tion of the result following if the subscrib I ers line is'busy. I Conside'ringnow the result if the called line is not busy, it will be evident that the'side switch passes to third position, thus placing the side switch wipers 78, 79,. 80 and 7. 1 in contact with their respectivec'ontact points 119, 112, 88 and 104 in third position. side switch passes to third position a guarding potential is established for protecting the This potential extends from Furthermore, when the called line.

. ground G to the contact. point 88, side switch wiper 80,, relay "90, switch-shaft wiper 85, which latter engages the private contact of the called line. The said guarding potential closes an energizing circuit through the relay 90 of the connector C, in

v series with the bridge-cut oft relay 91 of the first-selector D. Furthermore, since the rep lay 92 of the selector D is connected in mul tiple with the bridge-eut-ofi relay 91 between the normal conductor 88 and battery B, the relay 92 also becomes energized. This energizing circuit extends from ground G contact point 88 to the side switch wiper 80, through the winding of the relay 90, private wviper '85, private normal conductor 88,. through the normal springs 93 and 94 from whence it divides, onepath being through i the bridge-cut-ofi relay 91 to the battery ,lead 4 1, and the other path being through the relay 92 to the battery lead 44, thence through battery B and to ground G. The

relay 91 upon energizing removes the bridge formed by the verticalnand rotary line relays of the selector D, from across the line. Therelay 92 upon energizing operates to close the springs 95 and 96 in contact, whereby a circuit is closed through the alarm bell '97. Said circuit extends from. ground G 1 through the bell 97, springs 95 and 96 to the battery lead 14, thence through battery B and to ground G. The ringing of the bell gives to the attendant an audible signal indicating that the line to which the detecting apparatus is attached has been called by a subscriber. Furthermore, the relay 90 upon which operate to place the front-release,

springs 101 and 102 in contact, the release of the central oflice switches does'not occur,

because the energizing circuit through the.

release relay 103 of the first-selector A and of the release magnet 100 is opened between the release magnet 100 and the battery lead 41 by the separation of the springs 98 and 99. The central ofiice switches thenremain in their operated positions, whereby the attenda'nt may trace the call from the called line at the selector D back to th connector C and then to ,the selector A, thus detecting the substation nated.

. In exchanges employing connectors of this 5 -typethat is, with the relay '90 in the prifrom whence the call origirate wipercircuit extending from the side switch wiper 80 to the private wiper 85- calls may be made and the, switches employed may be released in the usual manner, when the detecting device shown at H is not attached to the called line. In that case. the

current flowing through the relay90 in series with the bridge-cutoff relay 91 (which is wound to a resistance of fourteen hundred ohms) is not SllffiClGUt to operatively energize the relay 90. 'lhereforc, the relays 67 and, 68, upon energizing simultaneously when the calling subscriber restores his receiver to the switch-hook, now close an energizing circuit, when the springs 101 and i 102 engage, through the release relay 103 and release magnet in series, since the relay 90 does not operate to disconnect the 1 release magnet 100 from the batterylead 41 at the springs 98 and 99,

Returning'to the explanation of the call ing operation, it should be described hat in order to signal the called subscriber;the

calling subscriber presses the signaling button 25, placing the spring 26 in contact with the substation ground G, thereby energizing the vertical line relay 67. The path of the energizing circuit extends from ground G, contact point 28, spring 26, springs 32 and 33to the vertical line conductor 34, side switch wiper 40,'contact point 61, first-selector shaft wiper 36, trunk conductor 65, vertical relay 67 to the battery lead 44, thence through battery B and to ground G. It will be remembered that the connector side switch has passed from second to third position, andthat the, side switch wiper 74 is inengagerent with the contact point 104, thereby placing the vertical line relay 67 in control of the ringer relay 105 in the same manner in which the rotary magnet 81 came under the control of the vertical line relay 67 when the side switch passed from first to second position. Therefore, when the vertical line relay 67 presses the springs 69 and into eontact,th'e ringer relay 105' is energized by a flow of current from ground G to therelay springs 69 and 70, private magnet springs 7 2 and 73, side switchwiper 74, contact point 104 tothe ringer relay 105 and to the battery lead 44, th'e'nce through battery B and to ground G. The ringer relay upon energizing shifts the springs 106 and 107 from the springs 108 and 109 and onto the springs 110 and 111, respectively. This results in the separation of the calling subscribers line from'the called subscribers line, and in bridging across the line of the latter the terminals of the ringer generator 19. A signaling current is therefore sent from the generator E to the ringer relay springs 110 and 106, side switch wiper 79, contactpoint 112, connector shaft Wiper 84, normal conductor 87, rotary line conductor 114 to the ringer 115, springs 116, switchhook 117 to the vertical line conductor 118 normal conductor 86, connector shaft Wiper 83, contact point 119, side switch wiper, 78,

. ringer relay'springs 107 and 111 back to the generator E. As soon as the calling subscriber ceases to press the signaling button 25 the ringer relay 105 becomes deenergized, and the springs 106 and 107 resume their normal position in contact with the springs 1108 and 109, respectively. The subscriber at substation #220 in response to the signal removes the receiver 120 from the switchllOOk 117, thereby removing the ringer 115 from across his line and bridging the secw ondary circuit instead, which circuit includos the receiver 120, secondary winding 12] of: the inductioircoil 122 and the springs 123 and 124. The local transmitter circuit is closed as soon as the springs 125 and 126 engage in contact.

.10 and #220 are now connected overthe circuit shown in heavylines on the drawing.

The so-called front release of the central ollice switching apparatus occurs when the calhng subscriber restores the receiver 2 to The two substations springs 29, 30 and 31 into engagement for a the switch-hook 3, thereby pressing the,

moment. The contact of the said release conductors 34 and 35 simultaneously from ground G to the release spring 29, thence through the springs 30 and 31 to the vertical springs grounds the vertical and rotary line and rotary line conductors, causing the energization of the connector line relays 67 i and 68, which in turn operate to close a cir- -v cuit through the relay 103 of the first-selector A in series with the release magnet 100 of the connector 0, as follows: The path of the current extends from ground G to,

the contact point 64, side switch wiper 60, release relay 103, first-selector switch-shaft wiper 38, connector. trunk-release springs 101 and 102, release magnet 100, springs'99 and 98 to the battery lead 44, thence through 1 battery ,B and to ground G.. When the connector release magnet 100 is thus supplied;

with current it energizes, and as a result the switch-shaft nd side switch .of the conneci breaking the connection between the con-j .tor, are res ored to normal position, thus nector switch-shaft wipers 83, 84 and and: a the normal conductors 86, 87 and 88. The back-release relay 103 of the first-selector A, a j being in the same circuit as the release mag- 4 net,l00, energizes simultaneously with the latter, and presses the springs 12'? and 128 intoengagement, which in turn close an energlzing circuit through the release magnet 129 of the first-selector A. This circuit eX- tends from ground G through the release relay springs 127 and 128, through the winding of the release magnet 129 to the battery lead 44, thencev through battery B and to ground G. All the relays and magnets thus! energized attract their respective armatures, and as soon as the substation release springs 29, 3O and'31 separate and break the ground connection with the conductors'34 and 35,

they again deenergize. The calling sub- 3 .110

scriber thus restores'all switching apparatus which he originally brought into use.

The back-release or back-bridge relays 135 and 136 are provided in order that the called subscriber may 'not remain helplessly tied up, so to speak, while the bridge-cut-ofl' relay restoring the receiver 120 to the switch-hook 117, and thus press the release springs 132, 133 and 134 into engagement. As a result an energizing current will pass through the vertical back-bridge relay 135 and the rotary l back-bridge" relay 136 of thef connectori C. 'The circuit through the vertical back-bridge relay extends from thesubstation ground G to the-groundisprings l30and=131to the springs 134 and 133, vertical line conductor 118, normalconductor 86,. shaft. wiper 83, contact point 119," side switch 1 wiper .78, ringer.relay springs-107 and 1O9, vertical back-bridge relay 135 to the battery lead 44:, 1o" thence through battery Bzand'to ground G.

The energizing circuit of the-back bridge rei any 136 extends {from ground Gflrelease v springs1-34, 133 1' and 132 to the'frot'ary line conductor 1 14, normalconductor 87, shaft '15 wiper 84, @contact' point. 112', side switch wiper79, ringer relay";springsyhhiv and 108 i and rotary balcl r-bridge;rel'ay,136 to the bat- 5 'teiy leadj lt, thence throughbatteryB and .to ground G. The back-bridge, relays 135 and 13,6 upon energizing simultaneously.

press the" back-release springs. 137 and 138 into contact, Which completes an 'energizing circuit to the release magnet 1Q0 from ground G to ;the springs 137 and C138,

through the release magnet 100, springs 99 and 98 to the battery leadjta, thence through batteryB and to ground GafThe releasev magnet is thus energized and the switch:

shaft wipers 83, Stand .85 and side switch, arerestored'to normal position. The enerecgizi-ng circuit through the bridgehu't-oil 5 relay 9151s brokenwhen the shaftwiper 85; leaves the private bankcontact 'andthus the -connector. switch C isfre'leased and the: first selector D is restored of substation #220,? The subscriber' atsubstation #500 may; restore the first-selector A" by grounding the line conductors 34 and 35.

It is evident iromthe foregoingthat our 9 mventronprovides al meansf for-"locating a subscriber who may be annoying some other subscriber. If complaintg'is made, that a certain subscriber isbeing annoyed by an unknown party, the detectiu device may be connected (as shown at, H to the firstselector allotted to the complaining line;

1 then when any connector of the exchange connects with tlie said line a circuit is completed which automatically locks the said connector in its operated position, and at the same time another circuit is closed which may either ring a bell or light a lamp, indlcating to the attendant that the complaining line has been seized. The attendant may then easily trace the call back from. the

connector to the calling first-select0r and,

therefore, determine from which substationwthe call originated. The attachment H is,

of course, movable, but the relay 90 is per :manently connected to the private wiper circuit of t connector 0.

The relay. OQand 92 may bewoundfto' any suitable resistance, butwith a central battery of fifty volts good results have been obtainedwhen relay'zflQ is-wound to, a re-f to the direct tunnel adapted to make connection with anyone ",e e itii a c llil atiesa.

sistance of one-half ohm and relay 92 to a resistance of thirty ohms. The reason for winding the relay 90 to about one-half ohm' .is as follows: If any other connector switch plied in the well-known manner through the private shaft wiper and side switch.

wiper 80 of the connector C, except thatin this case the current would have to pass 0 through the relay 90,Zand if this relay were ofhigh resistance the relea'semagnet of the I second calling connector would not receive sufficient current to operatively energize it.

It will be seen that-weprovide a, call- 35 locating device whichcan be applied to any line for'the purpose of tracing all calls coming onto such line. e alsoprovide a signal which can beindividua'l to a single line'and. which indicates .:.when the line is called.

The connector 0 cani'be employed on. a

"percentage-basis, thus, making them-less in number than the subscribers. :iFor example, a group of one hundred subscribers need have only ten connectors. for accommodating all calls coming onto'th'eir lines. 1 The first selectors can also be arranged on a. percentage basis, any known orfsuitable manner.

If necessary, second "or third selectors may loo bgaemployedin order to provide. automatic trunking in a larger exchange. With the arrangement shown the first-selectors are sufficient for automatically trunking to idle connectors. What we claim as'ourinventionis:-, 1. In a telephone exchange "system, the combination of telephonee'lines, connectors less in number than said lines, adapted to make connection with any one'thereof, means- 11% for automatically trunking'acalling line to an idle connector, means. for operating said connector, and a call-locating device;

applied to a certain one of said lines, adapt ed to cooperate with any calling connectorl ir in preventing a release vwhen"said certain line is called. a I

2. In a telephone exchangeisystem-the combination of telephone lines, connecto isk I20 thereof, means for automatically 'trunking'aj calling line to an idle connector, means for operating said connector, and a call-locating device applied to a certain one of said linesf adapted to cooperate with any calling @611. nectorin preventing a release when, said certainjline is called. 1. 5.", f 3,-An automatic connectoraprovided with a releasejcircuit, a relay.

w energized to prevent the operation of said mechanism, and means for energizing said relay when the connector is used for calling a certain subscriber.

5. The combination of a group of telephone lines, connectors less in number than said lines, each adapted for connecting with any one thereof, and means applied to one of said lines to non-releasably retain any calling connector thereon.

6. An automatic telephone exchange system provided with a call-locating device adapted to be made temporarily individual to any called subscriber thereof, to prevent disconnection between the subscribers, provided with means for giving a signal.

7. In a telephone system divided into groups, the combination of telephone lines, connectors less in number than said lines, adapted to make connection with any one thereof, means 01- automaticallytrunking a calling line to an-idle connector, means for operating said connector, and a call-locating device applied to a certain one of said lines, adapted'to cooperate with any calling connector in preventing a'release when said. certain line is ca'lled, said connectors having one motion to select groups and another motion to find the called line in any selected group.

8. In a telephone system divided into groups, an automatic connector provided with a release circuit, a relay for opening said circuit, and a'calllocating device for causing the saidrelay to energize when the connector is used for calling a certain subscriber, said connector havingv one motion to select groups and another motion to find the called line in any selected group.

9. In a telephone system divided into groups, an automatic connector provided with release mechanism, a relayadapted when energized topreventthdoperation of said mechanism, and means for energizing said relay when the connector is used for calling a certain subscriberysa' d connector having one motlon to select groups and an other motion to find the called linein any selected group.

10. In a telephone system divided into groups. the combination of a group of telephone lines, connectors less'in number than said lines, each adapted for connecting with any one thereof, and means applied to one .of said lines to retain any-calling connector thereon, said connectors having one motion to select groups and another motion tofind the called line in any selected group.

11. An automatic telephone exchange system' having lines divided into groups, hav-j ,ma de with a called linei individual switclil mg means for selecting the groups by verti I cal motion and the lines by rotarymotion, provided with a call-locating device adapted to be made temporarily individual to any, called subscriber thereof, to prevent disconnection between the subscribers, I provided with means for giving a signal.

12. In a telephone system, means by which the calling subscriber extends connection to the called line, means for releasing said connection controlled by a subscriber, and means for preventing the calling subscriber from controlling said releasing means.

13. In a telephone system, subscribers lines, an automatic connector switch for connecting with a called line, a release magnet,

a relay controlling normally closed contacts in the circuit of said release magnet and means for operating said relay to open said release circuit when connection is made with a subscribers line. Y i

ll. In a telephone system, subscribers lines, an automatic connector switch for connecting with a called line, a release magnet,

a relay controlling normally closed contacts in thecircuit of said release magnet, and means for energizingsaid relay when con; nection is made with a called line.

15. In a telephone system, subscribers 7 lines, an automatic connector switch for con-' necting with a called line, a release magnet,

a relay controlling normally closed contacts in the circuit of said release magnet,1 a circuit for said relay including a high resistance, and means for closing a parallel con-x 10 .nection around said high resistance, whereby sufficient current passes through said re-' lay to energize the same. i 16. In a telephone system, subscribers lines, an automatic connector switch for connecting with a called line, a release magnet, a relay controlling normally closed contacts in'the circuit of saidrelease magnet, a par- I allel connection, and a signal-controlling, f' 1 means in saidparallel connection whereby an indication is given-when a connection is 17. In a telephone systemji'subscribers" lines, a switch for connecting with-any one of said'lineaa release magnet therefor, a relay for controlling the circuito'f Saidreleasennagnet, a switch individual to a sula scribers line, and an energizing circuit'for,

said relay including a second relay in. said-Rf) 129 18. In a telephone system," subscribers lines, a switch. for connecting witlran one,-.: of said lines, a release magnet therefor, a relay for controlling the circuit of said release magnet, a-switch individual to a sub,- 1. 'scribers" line, a high resistance relay and a low resistance relay in said individual switch, and an energizing circuit- -for said first-mentioned relay including said last-- mentioned relays in series. 1 im I 19. In a telephone system subscribers lines, a switch for connectingwith any one of saidlines, a release magnet therefor, a

relay for controlling the circuit ofsaid re? 5 leasemagnet, :a sw tch llldlfldllttl to a subscribers line, a high resistance relay and a low resistance "relay in said ind vidual switch, an energizing circuit for said firstmentioned relayincluding said last-men tioned relaysin series, and a. signal con-- trolled by said low resistance relay whereby an indication is given'whenalconnection is anade with a called line; i

, 20. In a telephone-system, subscribers connector switch having motion in one "plane to select groupahndmotion in aplane.

, Lat rigl it anglesthereto .toffind a line in the 1 line, a release magnet, a'relaycontrolling normally closed contacts in the circuit of said release magnet, and meansfor operating said relay to opensaidrelease when connection is made with -a,subs cribers line,

lines-divided into groups, an automatic connector switch having motion in .one plane is ,select groups, and motion in a plane. at 'rightnngles thereto to find-a line in the sef-loflected group, for eonnectingwith a called line, a release magnet, a relay "controlling normally closed contacts'finfthe; circuit of said release magneaand. means for energizing ,sa-id relay when connect on is made with a called line. i 7

lines divided into-groupa an automatic 0011a rector switch having motion "in one plane. to

? l'ectedgrcum'for connecting withf'a called line, a release magnet, a relay controlllng I normally closed contacts in-the circuit of ;said release magnet, a circuit for said relay ,inclnding a high resistance, and means for closing a parallel connection around said h resistance, whereby snflicient current s through said relay to energize the same. a In a telephone system, subscribers 7 lines divided into groups, an automatic con- "ncctor switch havin'gmotion in one plane to select groups, and motion in a plane at rightangles thereto to find a line in the selected group, forconnecting with a called glines divided into groups, an automatic.

.. Jselected group, for connecting with a called 21: Ina telephone system, subscribers In a telephones'ystem', subscribers? v, 4 ect groups, and mo'tion A in a plane at in r ght-angles thereto to find a line" 1n the seline, a release magnet, a relajcozitrolling normally closed contacts in the circuit of said release magnet, a parallel connection, and a signal-controlling means in said parallel connection whereby an indication is given when a connection'ismade with a called line, I

24. In. a telephone system, subscribers lines divided into groups, a switch having motion in one plane to select groups, and

motionin a plane at right-angles thereto to find a line in the selected group, for connecting with any one of said lines, a release magnet therefor, 'a'relay for controlling the circuit of said release magnet, a switch individualr to a subscribers line, and an enere gizing circuit for said relay.includin,g a"second relay in said individual switch.

25. In a telephone System, subscribers lines divided into groups, a switch having motion in one plane to select groups, and

motion in a plane at right-angles thereto to find a line in the selected group, for con- 'nectlng wlth any one of sald lines, a release magnet therefor, a relay for controllingvthe circuit of said release'magnet, a switch. individualto a subscribers line, a high resistance relay and a low resistance relay in said individual switch, and an energizing circuit for said first-mentioned relay including said last-mentioned relays in series.

lines divided into groups, a switch having motion in one plane to select groups, and anotion in a plane at 1'ightangles thereto to find a line in the selected group, for connecting with any one of said lines, a release 26. In a telephone. system, subscribers magnet therefor, a relay for controlling the Y circuit of said release magnet, a switch indlvldual to a subscr1ber.s line, a high resistance relay and a low resistance relay in 

